O presente trabalho aborda três tópicos de pesquisa e desenvolvimento em Sistemas de Posicionamento Dinâmico (SPD). Desenvolveu-se uma nova metodologia para o projeto de controlador de posição e aproamento baseada na teoria de controle robusto não-linear por modos deslizantes. O controlador integra uma malha de compensação direta dos esforços ambientais (ondas, vento e correnteza) a uma malha de realimentação que realiza correções de erros residuais. A estrutura não-linear do controlador assegura o desempenho e estabilidade para qualquer aproamento da embarcação. A malha de compensação direta, por sua vez, garante maior faixa de aplicabilidade em termos de condições ambientais, não apresentando degradação de desempenho em condições extremas. A malha de realimentação possui apenas nove parâmetros, existindo equações e regras que tornam suas calibrações simples. Já a malha de compensação direta possui, internamente, modelos para a estimativa das forças ambientais que agem sobre o navio. Graças às características de robustez, o controlador não requer um ajuste refinado dos diversos parâmetros destes modelos e das condições ambientais, podendo-se utilizar estimativas pouco acuradas dos mesmos. O controlador desenvolvido foi testado em simuladores computacionais do VLCC Vidal de Negreiros amarrado pelo sistema turret e de uma barcaça de lançamento de dutos, ambos contendo modelos validados dos esforços ambientais. As simulações emularam erros de modelagem e de estimação das condições ambientais, e confirmaram as boas características de robustez e desempenho do controlador em diversas condições e a facilidade no ajuste de parâmetros. Desenvolveu-se também um modo de controle apropriado para operações com liberdade de aproamento realizadas na Bacia de Campos, onde é comum a incidência de agentes ambientais em direções não alinhadas. Neste modo calcula-se, baseado nas estimativas das condições ambientais, o aproamento que minimiza um funcional relacionando parâmetros operacionais relevantes, como movimento de roll, tração dinâmica em risers, solicitação do sistema de amarração e consumo de combustível. Uma análise numérica de sensibilidade, aplicada ao VLCC Vidal de Negreiros, indicou que o cálculo do aproamento ótimo não apresenta elevada sensibilidade a erros nas estimativas das condições ambientais em condições extremas. Testes numéricos comprovaram também a superioridade do presente modo de controle comparado ao tradicional modo Weather vane nas condições da Bacia de Campos. Como a estimação do espectro de ondas incidentes ainda apresenta problemas técnicos e operacionais, desenvolveu-se também um método de estimação do espectro baseado na medição dos movimentos da embarcação. Utilizou-se uma abordagem paramétrica, cuja sensibilidade a erros no conhecimento da resposta dinâmica da embarcação mostrou-se aceitável. O método foi testado numericamente e validado com resultados de ensaios em tanque de provas. Os erros de estimação foram plenamente compatíveis aos erros admissíveis pelo controlador desenvolvido, alcançando, no caso da altura significativa, o valor máximo de 25%. O método foi comparado à abordagem não paramétrica Bayesiana, muito utilizada em trabalhos correlatos, e apresentou resultados mais acurados. / The present work deals with three research and development topics related to Dynamic Positioning Systems. A new design methodology of ship position and heading controller was developed, based on the robust and nonlinear Sliding Mode Control theory. The controller contains a feedforward action, which compensates environmental forces (wind, waves and current) and a feedback loop, responsible for the elimination of residual errors. The nonlinear formulation of the controller assures performance and stability requirements for all heading angles. The feedforward action guarantees its applicability in a large range of environmental conditions, without performance degradation in severe conditions. The feedback loop contains only nine parameters, which can be calibrated easily by simple equations. The feedforward loop internally contains models for the estimation of the environmental forces acting on the ship. However, due to robustness properties, the controller does not require a fine adjustment of its several parameters and the environmental conditions, allowing the use of non-accurate estimates. The controller was tested in computational simulators of the turret moored VLCC Vidal de Negreiros and of a pipe-laying barge, both comprising validated models of environmental forces. The simulations emulated modeling and environmental conditions estimation errors, confirming the good robustness and performance properties of the controller in several environmental conditions and the simple parameter adjusting process. A control mode adapted for heading-free operations in Campos Basin was also developed, where non-aligned environmental agents frequently happen. In this mode, it is calculated the optimal heading that minimizes a functional relating important operational parameters, such as roll motion, risers dynamic tension, mooring system forces and energy consumption. Estimations of environmental conditions are used in the calculation. However, a numerical sensibility analysis of this control mode applied to the VLCC Vidal de Negreiros indicated that the optimal heading calculation presents low sensibility to errors in these estimations under severe environmental conditions. Numerical trials showed that this control mode is more adequate to Campos Basin conditions compared to the traditional Weather vane mode. Since wave spectrum estimation still presents technical and operational problems, a spectrum estimation method was also developed, based on measurements of ship motions. A parametric method was used, which presented low sensitivity to errors in ship dynamic response functions. The method was numerically tested and validated through towing tank tests. Estimation errors were compatible to the controller admissible errors. For example, the maximum error in significant wave height estimation was 25%, smaller than the errors usually obtained using the non-parametric Bayesian method, widely applied for this class of problems.

Neste trabalho é proposto um estudo envolvendo o controle vetorial do Motor de Indução Trifásico, compreendendo o uso da teoria de modos deslizantes nas malhas de controle de fluxo e velocidade na estratégia de Controle Vetorial por Orientação Indireta de Campo (Indirect Field Oriented Control, IFOC), visando sobretudo, melhorar tanto o desempenho dinâmico quanto o problema de chattering. Para tanto, aborda-se o uso de uma função de chaveamento suave, analisando suas características perante o uso de diferentes superfícies de deslizamento. Com base nessas análises, tem-se a proposta de um controlador por modos deslizantes integral, englobando o uso de uma superfície de deslizamento integral em conjunto com um método de anti-windup, sendo tal método baseado em uma função triangular. Para verificar a atratividade às superfícies de fluxo e velocidade, é realizada uma investigação quanto ao uso de uma parcela paramétrica como ação de controle, dada pelo termo equivalente. Com o objetivo de analisar a topologia de controle proposta, resultados são obtidos por meio de simulação e de uma bancada experimental considerando diferentes condições de operação. Desta forma, os resultados foram divididos em testes, visando abordar o problema do chattering e diferenças do controlador proposto perante os convencionais. De maneira geral, a topologia de controle apresentou resultados melhores aos encontrados na literatura, podendo ser uma opção em sistemas que requerem acionamento de alto desempenho dinâmico. / This work deals with the vector control in a three-phase induction motor, applying the sliding mode theory to both the flux and the speed control loops in the Indirect Field Oriented Control strategy. It aims to improve the dynamic performance regarding the chattering problem. Therefore, the use of a smooth switching function is addressed, analyzing the outcomes achieved by different sliding surfaces. Based on these analysis, an Integral Sliding Mode Controller is proposed employing an integral sliding surface along with an anti-windup method based on a triangular function. In order to verify the attractiveness of the flux and the speed surfaces, an investigation regarding the use of a parametric portion as control action is carried out. The proposed control strategy is verified by means of simulations and experiments on test bench for different operating conditions. This way, the results are split in tests aiming to approach chattering problems and the differences between the proposed and traditional control strategies. Genarally, the outcomes of the proposed topology are better with those found on literature, pointing it as a viable choice to drive high dynamic performance demanding systems.

In this thesis a class of robust non-linear controllers for a gantry crane system are discussed. The gantry crane has three degrees of freedom, all of which are interrelated. These are the horizontal traverse of the cart, the vertical motion of the goods (i.e. rope length) and the swing angle made by the goods during the movement of the cart. The objective is to control all three degrees of freedom. This means achieving setpoint control for the cart and the rope length and cancellation of the swing oscillations. A mathematical model of the gantry crane system is developed using Lagrangian dynamics. In this thesis it is shown that a model of the gantry crane system can be represented as two sub models which are coupled by a term which includes the rope length as a parameter. The first system will consist of the cart and swing dynamics and the other system is the hoist dynamics. The mathematical model of these two systems will be derived independent of the other system. The model that is comprised of the two sub models is verified as an accurate model of a gantry crane system and it will be used to simulate the performance of the controllers using Matlab. For completeness a fully coupled mathematical model of the gantry crane system is also developed. A detailed design of a gain scheduled sliding mode controller is presented. This will guarantee the controller's robustness in the presence of uncertainties and bounded matched disturbances. This controller is developed to achieve cart setpoint and swing control while achieving rope length setpoint control. A non gain scheduled sliding mode controller is also developed to determine if the more complex gain scheduled sliding mode controller gives any significant improvement in performance. In the implementation of both sliding mode controllers, all system states must be available. In the real-time gantry crane system used in this thesis, the cart velocity and the swing angle velocity are not directly available from the system. They will be estimated using an alpha-beta state estimator. To overcome this limitation and provide a more practical solution an optimal output feedback model following controller is designed. It is demonstrated that by expressing the system and the model for which the system is to follow in a non-minimal state space representation, LQR techniques can be used to design the controller. This produces a dynamic controller that has a proper transfer function, and negates the need for the availability of all system states. This thesis presents an alternative method of solving the LQR problem by using a generic eigenvalue solution to solve the Riccati equation and thus determine the optimal feedback gains. In this thesis it is shown that by using a combination of sliding mode and H??? control techniques, a non-linear controller is achieved which is robust in the presence of a wide variety of uncertainties and disturbances. A supervisory controller is also described in this thesis. The supervisory control is made up of a feedforward and a feedback component. It is shown that the feedforward component is the crane operator's action, and the feedback component is a sliding mode controller which compensates as the system's output deviates from the desired trajectory because of the operator's inappropriate actions or external disturbances such as wind gusts and noise. All controllers are simulated using Matlab and implemented in real-time on a scale model of the gantry crane system using the program RTShell. The real-time results are compared against simulated results to determine the controller's performance in a real-time environment.

Uno de los campos más importantes de la Electrónica de Potencia es el de los convertidores de potencia conmutados, que debido a sus características de alto rendimiento energético, reducido tamaño, posibilidades de regulación del factor de potencia y de elevación de tensión, etc., están presentes en un gran número de las etapas de alimentación de los equipos electrónicos actuales.Las mejoras tecnológicas en ámbitos como el de la integración de circuitos han permitido importantes reducciones en el tamaño de los equipos (por ejemplo en los ordenadores). Sin embargo, este proceso de reducción de tamaño que, además, suele venir unido a unas especificaciones más rígidas en cuanto a costes, rendimiento, seguridad y prestaciones en general, no se ha producido en igual medida en las etapas de alimentación. El estudio de los convertidores conmutados es por lo tanto un campo necesitado de esfuerzos de investigación y desarrollo.Para potencias superiores a 25 W, y especialmente en potencias superiores a 150 W, una de las estrategias utilizadas para mejorar las prestaciones de los convertidores es el uso del denominado "interleaving" o entrelazado , definido como la puesta en paralelo de N convertidores idénticos desfasando sus señales de control de forma uniforme a lo largo del periodo de conmutación.Con el objetivo principal de reducir al máximo los rizados de la tensión de salida y de la corriente de entrada, en esta tesis se estudian casos particulares de "interleaving" en estructuras convertidoras continua-continua que utilizan el convertidor elevador ("boost") como célula básica y cuyas tensiones de salida son, idealmente y operando en modo de conducción continua, múltiplos enteros positivos de la tensión de entrada, de ahí la denominación de multiplicadores de tensión que aparece en el título de tesis propuesto. Posteriormente se analizan las posibilidades de regulación de tensión que presentan algunos de los casos de estudio, a costa de incrementar los rizados.

In order to have an interception with a target, a missile should be guided with a successful guidance algorithm accompanied with a suitable autopilot structure. In this study, different autopilot and guidance designs for a canard-controlled missile are developed. As a first step, nonlinear missile mathematical model is derived by using the equations of motion with aerodynamic coefficients found by Missile DATCOM program. Autopilot design starts by the linearization of the nonlinear missile model around equilibrium flight conditions. Controllers based on the concepts of optimal control theory results and sliding mode control are designed. In all of the designs, angle of attack command and roll angle command type autopilot structures are used. During the design process, variations in angle of attack, Mach number and altitude can lead to significant performance degradation. This problem is typically solved by applying gain-scheduling methodology according to these parameters. There are different types of guidance methods in the literature. Throughout this study, proportional navigation guidance and its modified forms are selected as a base algorithm in the guidance system design. Other robust forms of guidance methods, such as an optimal guidance approach and sliding mode guidance, are also formed for performance comparison with traditional proportional navigation guidance approach. Finally, a new guidance method, optimal proportional-integral guidance, whose performance is the best among all of the methods included in the thesis against highly maneuvering targets, is introduced.

Based on sliding-mode control theory, this thesis proposes an integrated design of robust speed controller and quantized current regulator to achieve the control of inverter for BLDC motor. Moreover, using Digital Signal Processor (DSP) as well as the proposed inverter technology as the control kernel, a fully digital drive module of Brushless DC motor (BLDC) is robustly designed to achieve the high-performance speed control. Under the influence of system disturbances, the designed drive module can obtain a good tracking response for speed and current control. According to the simulation and experimental studies, the proposed hybrid control strategy can simultaneously achieve the objective for the speed and current control of BLDC motor. Compared with traditional pulse-width modulation (PWM) based PID control, the better speed control performance can be conducted by the provided approach.

Für drehzahl- und lagegeregelte elektrische Antriebssysteme mit mechanisch-elastischen Übertragungselementen exitiert eine Fülle von Regelstrategien. Jede von ihnen weist spezifische Vor- aber auch Nachteile auf, welche letztlich auf die eigene prinzipbedingte Güteschranke zurückzuführen sind. Um eine solche Güteschranke zu durchbrechen muß man grundsätzlich die Strukturbeschränkung des Reglers angreifen. Hierfür werden zwei Möglichkeiten aufgezeigt, ein parametervariables und ein strukturvariables Regelkonzept. Mit der Parameter-und der Strukturvariabilität lassen sich konventionelle Regler qualitativ aufwerten, und unterschiedliche Regelprinzipien kombinieren. Insbesondere können Nutz-Nichtlinearitäten in systematischer Weise in lineare Regler integriert werden. Das parametervariable Regelkonzept verfolgt dem Ziel, das dynamische Regelverhalten konventioneller Regler durch Online-Tuning der Reglerparameter zu verbessern. Hierbei können unterschiedliche Parametersätze vorteilhaft kombiniert werden, so dass die Güteschranke des konventionellen Reglers überwunden wird. Der systematische Entwurf vereint die klassischen linearen Methoden mit der heuristischen fuzzy-basierten Vorgehensweise. Beim strukturvariablen Konzept handelt es sich um ein auf das Sliding-Mode-Prinzip basierte Regelverfahren, dessen Hauptgegenstand die Güterobustheit der Regelung gegenüber Parameterunsicherheiten ist. Um die Nachteile des Sliding-Mode-Prinzips zu vermeiden und damit die Realisierbarkeit für elektrische Antriebssysteme zu erhöhen, werden Methoden für die Rekonstruktion der Zustandsgrößen und für die Chattering-Reduktion vorgeschlagen. Auch das strukturvariables Konzept beinhaltet einen starken Bezug zu linearen Prinzipien. Möglichkeiten zur Kombination beider vorgeschlagenen Konzepte werden ansatzmässig aufgezeigt. Die beiden Konzepte werden in Simulation und an einer Versuchsanlage experimentell erprobt

Dans un contexte comme celui des technologies aérospatiales, qui se caractérise non seulement par sa complexité, mais aussi par sa difficulté à régler les erreurs une fois que le véhicule est dans son environnement final, l’utilisation des simulateurs de satellite sur Terre pour le développement et la vérification de nouveaux systèmes offre une alternative intéressante aux simulations traditionnelles par ordinateur. Plus précisément, dans le cas de la commande d’attitude, la possibilité d’utiliser la dynamique réelle du satellite pendant les phases de conception et de développement présente des avantages tels que l’inclusion des systèmes difficiles à modéliser et la réduction du risque d’erreur et du temps de vérification. Cependant, cette technologie est encore récente et est de ce fait sujette à être améliorée afin d’offrir le meilleur scénario possible pour le développement des algorithmes de commande d’attitude de la prochaine génération de satellites. À cet effet, l’Université de Sherbrooke et la société NGC Aérospatiale Ltée. développent en partenariat le simulateur matériel de satellite LABSAT qui possède toutes les fonctionnalités d’un véhicule spatial incluant les actionneurs, capteurs, calculateurs embarqués et éléments flexibles. Le projet présenté dans ce document consiste à concevoir et mettre en œuvre sur le minisatellite LABSAT un premier système de navigation et commande permettant d’exécuter les manœuvres en orientation à partir d’une station de contrôle. À cette fin, les différents sous-systèmes du simulateur matériel ont été intégrés et des solutions en termes de calibration de capteurs, d’estimateur d’état et de systèmes de commande ont été analysées théoriquement et en simulation. Les techniques les plus appropriées ont été, par la suite, implémentées et évaluées sur le système final, dans le but de vérifier leur fonctionnement dans l’environnement réel.

In this thesis a class of robust non-linear controllers for a gantry crane system are discussed. The gantry crane has three degrees of freedom, all of which are interrelated. These are the horizontal traverse of the cart, the vertical motion of the goods (i.e. rope length) and the swing angle made by the goods during the movement of the cart. The objective is to control all three degrees of freedom. This means achieving setpoint control for the cart and the rope length and cancellation of the swing oscillations. A mathematical model of the gantry crane system is developed using Lagrangian dynamics. In this thesis it is shown that a model of the gantry crane system can be represented as two sub models which are coupled by a term which includes the rope length as a parameter. The first system will consist of the cart and swing dynamics and the other system is the hoist dynamics. The mathematical model of these two systems will be derived independent of the other system. The model that is comprised of the two sub models is verified as an accurate model of a gantry crane system and it will be used to simulate the performance of the controllers using Matlab. For completeness a fully coupled mathematical model of the gantry crane system is also developed. A detailed design of a gain scheduled sliding mode controller is presented. This will guarantee the controller's robustness in the presence of uncertainties and bounded matched disturbances. This controller is developed to achieve cart setpoint and swing control while achieving rope length setpoint control. A non gain scheduled sliding mode controller is also developed to determine if the more complex gain scheduled sliding mode controller gives any significant improvement in performance. In the implementation of both sliding mode controllers, all system states must be available. In the real-time gantry crane system used in this thesis, the cart velocity and the swing angle velocity are not directly available from the system. They will be estimated using an alpha-beta state estimator. To overcome this limitation and provide a more practical solution an optimal output feedback model following controller is designed. It is demonstrated that by expressing the system and the model for which the system is to follow in a non-minimal state space representation, LQR techniques can be used to design the controller. This produces a dynamic controller that has a proper transfer function, and negates the need for the availability of all system states. This thesis presents an alternative method of solving the LQR problem by using a generic eigenvalue solution to solve the Riccati equation and thus determine the optimal feedback gains. In this thesis it is shown that by using a combination of sliding mode and H??? control techniques, a non-linear controller is achieved which is robust in the presence of a wide variety of uncertainties and disturbances. A supervisory controller is also described in this thesis. The supervisory control is made up of a feedforward and a feedback component. It is shown that the feedforward component is the crane operator's action, and the feedback component is a sliding mode controller which compensates as the system's output deviates from the desired trajectory because of the operator's inappropriate actions or external disturbances such as wind gusts and noise. All controllers are simulated using Matlab and implemented in real-time on a scale model of the gantry crane system using the program RTShell. The real-time results are compared against simulated results to determine the controller's performance in a real-time environment.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 170-177).